Fuel Pump is Loud - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 4 (permalink) Old 12-29-2013, 12:21 PM Thread Starter
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Fuel Pump is Loud

my car seems to be running fine but i have noticed whenever my car is setting at a stop sign or traffic light, when my radio is quiet and my heater is off, i can faintly hear my fuel pump making a odd sound (atleast i think its my fuel pump)

it sounds like it is almost pulsing pretty fast, thats about the best im able to describe what its doing. its not loud at all and like i said my car runs fine. i would say most people would just brush it off but it just does not seem right to me.

just a little over a year ago my fuel pump went out (actually the plastic lines cracked). i know about the recall but my pump went out about 3 months before the recall, i replaced the pump and fuel filter myself and because i did it and not a chevy dealer i was not able to get a refund for the pump i bought when the recall came out.

so with that being said, the pump and filter is just over a year old and the noise had just started about a month ago.

my thoughts are maybe the fuel filter is clogged and not letting gas though fast enough to get to the pump, but i would think that would make my car stumble. i would sure hate to think the pump is bad, the pump is a chevy issued pump not a cheap advance auto parts pump so i would expect this pump to last years. the pump and filter only have about 10,000 miles on it, i wouldnt even expect the filter to get that clogged that soon.

could someone help me out here because i am stumped. it could be nothing but i am just afraid my pump may go out and leave me stranded.

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post #2 of 4 (permalink) Old 12-30-2013, 04:22 AM
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The fuel pump module (all in one unit) is an electric pump, it makes a interesting whine sound when first fired up and generally the engine noise will overcome that whine. For the pulsating sound, it maybe your EVAP canister clogged up. They have been known to clog up from a few other cobalt owners.

Your fuel pump filter is a strainer built on the pump module, you can clean it, but it should not generally give out or clog up within the first year. My strongest suggestion for you is to pull out your spark plugs and you can see if your burning correctly the right amount of fuel. If it shows lean condition on the plugs, you should be able to take back your fuel pump unit and with the recall inquiry at no cost to you.

Is your check engine light illuminated?

The reason why I say "pull out your spark plugs" is to save your grief in your combustion chamber. You can google spark plug wear indicator charts and it should pop up a bunch of pictures and a brief explanation of what each wear indicates. If its lean, then you know for a fact that your fuel system is causing the problem. Its much easier than pulling out your fuel pump module from under the back seat and finding out, that's not the problem.

2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille

Last edited by 5t3alth; 12-30-2013 at 04:25 AM.
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post #3 of 4 (permalink) Old 12-31-2013, 08:57 AM Thread Starter
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thanks for the reply, i will have to take a look at my plugs when i have a chance. my check engine light is not on, my car seems to run perfectly too. i may be looking too much into this, its just a odd sound that has just started. i know its normal that some fuel pumps are loud but this seems like a different kind of noise because of the pulsing sound.

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post #4 of 4 (permalink) Old 01-13-2014, 01:15 PM Thread Starter
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i have some free time this coming weekend so im planning to hopefully trouble shoot until i find what is wrong.

now i did take some time to crawl under my car to try to listen where the noise was coming from. i am 98% sure it is my fuel pump. with that being said, there is one single fuel line going to my fuel filter, on the other side of the fuel pump there is two plastic lines coming out from it.

i laid and watched them two plastic lines for a while and when my car makes the "pulsing" sound them two lines flex. i can physically see them move and when i held them i could feel them also. its almost like when the fuel goes through it pulses and that is making the noise and making the two lines move.

could anyone make heads or tails out of this with the new additional info i gave about the lines?

keep in mind that the car runs flawless, i even took the RPM's up to 3500 going up a long hill and the car does not stumble what so ever.

i would greatly appreciate if someone could let me know what they think ASAP as i plan on working on it this weekend.

thanks in advance!

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